Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

Clydesdales/Athenas (200+ lb / 91+ kg) Looking to lose that spare tire? Ideal weight 200+? Frustrated being a large cyclist in a sport geared for the ultra-light? Learn about the bikes and parts that can take the abuse of a heavier cyclist, how to keep your body going while losing the weight, and get support from others who've been successful.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 07-26-08, 03:02 PM   #1
ModelT
Read, Ride, Repeat
Thread Starter
 
ModelT's Avatar
 
Join Date: Feb 2008
Bikes:
Posts: 58
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Road Bike, Mountain Gears?

Hello fellow Clydes and Athenas:

Me and my road bike have a very difficult time getting up hills.
Even in the 'Granny' front 30T ring and the big 25T back cog, I have to seriously mash the pedals to move up the mountain.
Is it possible to put a big 11-34 mountain/commuter cassette on a Trek 1500 Road Bike?

Anybody else have a similar issue?

Thanks
ModelT is offline   Reply With Quote
Old 07-26-08, 03:25 PM   #2
Mr. Beanz
Banned.
 
Mr. Beanz's Avatar
 
Join Date: Dec 2005
Location: Upland Ca
Bikes: Lemond Chambery/Cannondale R-900/Trek 8000 MTB/Burley Duet tandem
Posts: 20,030
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I've heard of some ridrs doing it but they had to replace the rear derailleur with a mountain bike type like an LX or an XT.

Roadie rear der's aren't able to handle taller cogs (gear rings).
Mr. Beanz is offline   Reply With Quote
Old 07-26-08, 03:38 PM   #3
Black Shuck
cycling n00b
 
Black Shuck's Avatar
 
Join Date: Jun 2005
Location: West Coast of Finland
Bikes: EAI Brassknuckle fixed Sannino fixed, Thorn Club Tour, Soma Smoothie
Posts: 582
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Shimano road derailleurs take up to 28t cogs, MTB derailleurs up to 34t, maybe more.
Black Shuck is offline   Reply With Quote
Old 07-26-08, 04:24 PM   #4
Wogster
Senior Member
 
Wogster's Avatar
 
Join Date: Jul 2006
Location: Toronto (again) Ontario, Canada
Bikes: Norco Bushpilot (out of commission), Raleigh Delta
Posts: 6,941
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by ModelT View Post
Hello fellow Clydes and Athenas:

Me and my road bike have a very difficult time getting up hills.
Even in the 'Granny' front 30T ring and the big 25T back cog, I have to seriously mash the pedals to move up the mountain.
Is it possible to put a big 11-34 mountain/commuter cassette on a Trek 1500 Road Bike?

Anybody else have a similar issue?

Thanks
The answer is a qualified maybe, it depends on the capacity on your rear dérailleur, what you need is a simple number, take the number of teeth on your largest chain-ring and largest gear, add them together, take the smallest chain-ring and smallest gear, add those together and subtract from the largest set, this will give you a number. You do this for the set you want, not the set you have. Now if you have Shimano components you go to the Shimano website and look up the rear dérailleur that you have, if it's capacity is more then the number you came up with, your fine, if it's smaller by say 1 or 2 your probably also okay, if more, then you will need to change the rear dérailleur for one that has a higher capacity, you will also need a new chain.
Wogster is offline   Reply With Quote
Old 07-26-08, 05:18 PM   #5
professorbob
Senior Member
 
Join Date: Jul 2008
Bikes:
Posts: 675
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I have something similar. A mountain crank and 12-26 8sp in the rear. It works well for me. I almost never need the granny, but it's there if I do.
professorbob is offline   Reply With Quote
Old 07-26-08, 05:36 PM   #6
Bill Kapaun
Senior Member
 
Bill Kapaun's Avatar
 
Join Date: Feb 2007
Location: Mid Willamette Valley, Orygun
Bikes: 86 RockHopper,2008 Specialized Globe. Both upgraded to 9 speeds.
Posts: 9,198
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 12 Post(s)
Quote:
Originally Posted by Wogsterca View Post
The answer is a qualified maybe, it depends on the capacity on your rear dérailleur, what you need is a simple number, take the number of teeth on your largest chain-ring and largest gear, add them together, take the smallest chain-ring and smallest gear, add those together and subtract from the largest set, this will give you a number. You do this for the set you want, not the set you have. Now if you have Shimano components you go to the Shimano website and look up the rear dérailleur that you have, if it's capacity is more then the number you came up with, your fine, if it's smaller by say 1 or 2 your probably also okay, if more, then you will need to change the rear dérailleur for one that has a higher capacity, you will also need a new chain.
You're describing chain wrap capacity.
That's only 1/2 the equation. The other 1/2 is maximum cog size.
Typical Shimano road RDER's won't handle a 34T cog. They are rated about 27-28, but will often handle a 30T.
Bill Kapaun is offline   Reply With Quote
Old 07-26-08, 06:55 PM   #7
sstorkel
Senior Member
 
Join Date: Apr 2008
Bikes: Cervelo RS, Specialized Stumpjumper FSR Pro, Schwinn Typhoon, Nashbar touring, custom steel MTB
Posts: 5,425
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Officially, Shimano says that rear derailleurs for road bikes max out with a 27-tooth cog. The guys over in the Mechanics forum will tell you that if you replace the "B adjustment" screw with a longer one, you can probably get away with running a larger rear cog. I have to admit that I haven't tried this myself, but it's probably the first thing I'd try if I wanted lower gearing on my road bike...
sstorkel is offline   Reply With Quote
Old 07-26-08, 07:28 PM   #8
CliftonGK1
Senior Member
 
CliftonGK1's Avatar
 
Join Date: Jul 2006
Location: Columbus, OH
Bikes: '08 Surly Cross-Check, 2011 Redline Conquest Pro, 2012 Spesh FSR Comp EVO, 2015 Trek Domane 6.2 disc
Posts: 11,380
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by sstorkel View Post
Officially, Shimano says that rear derailleurs for road bikes max out with a 27-tooth cog. The guys over in the Mechanics forum will tell you that if you replace the "B adjustment" screw with a longer one, you can probably get away with running a larger rear cog. I have to admit that I haven't tried this myself, but it's probably the first thing I'd try if I wanted lower gearing on my road bike...
I wouldn't try a 34t, but I managed to shoehorn an 11-32t PG-970 cassette on my Tiagra mid-cage RD. I'm running the stock Tiagra der's on my Cross Check, swapped out that cassette and the inner chainring (with a 34t) so I have a 34/32 combo on the low end. Not exactly mountain or touring gears, but it gets me and my groceries up and down the hills.
CliftonGK1 is offline   Reply With Quote
Old 07-27-08, 07:41 AM   #9
ModelT
Read, Ride, Repeat
Thread Starter
 
ModelT's Avatar
 
Join Date: Feb 2008
Bikes:
Posts: 58
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Experimental results:

I mounted an 8 speed mountain wheel with a 13-32 cassette on the bike to see what would happen.
(No riding here, just slow, no-load spinning to see what the rear derailleur would do)

It did actually shift up to the 32 cog, but made a lot of noise. I might try CliftonGK1's advice and try an 11-32 nine speed and see how much clearance the B screw can provide.

"I know just enough to be dangerous"
ModelT is offline   Reply With Quote
Old 07-27-08, 09:34 AM   #10
cohophysh
fishologist
 
cohophysh's Avatar
 
Join Date: May 2006
Location: Pacific Northwest
Bikes: Diamondback MTB; Leader 736R
Posts: 1,201
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I am no mechanic, but what about changing the the cassette in addition to the front chain ring to something similar to a mtb set up but still maintain the roadie components.
__________________
We cannot solve problems with the same level of consciousness that created them. A.E.

1990 Diamond Back MTB
2007 Leader 736R
www.cohocyclist.blogspot.com
http://www.loopd.com/members/cohocyclist/Default.aspx


cohophysh is offline   Reply With Quote
Old 07-27-08, 09:52 AM   #11
LarDasse74
Guest
 
Join Date: Jul 2008
Location: Grid Reference, SK
Bikes: I never learned to ride a bike. It is my deepest shame.
Posts: 3,769
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I replaced my b-tension screw with a longerone years ago and it worked well. I had several derailleurs ripped from my bike by stumps or sticks and the only replacement I could get was an old road derailleur. I used a long screw, bent it to hit the stop on the hanger and had my friend weld it in place. It worked great.

If I had to do the same thing today I would not, though. I would just go and buy a Deore derailleur. THey are cheap and they work well.
LarDasse74 is offline   Reply With Quote
Old 07-28-08, 08:07 AM   #12
Trebor Snave
Senior Member
 
Join Date: Jul 2007
Location: Helena, MT
Bikes: Specialized FSRxc Pro, Softride Norwester
Posts: 112
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
When we built up my bike, the only crank we had available was from a old mtb, so I've been running that with a regular road cassette on the rear all summer. There have been times I've really enjoyed that ultra granny gear.
Trebor Snave is offline   Reply With Quote
Old 07-28-08, 09:14 AM   #13
sstorkel
Senior Member
 
Join Date: Apr 2008
Bikes: Cervelo RS, Specialized Stumpjumper FSR Pro, Schwinn Typhoon, Nashbar touring, custom steel MTB
Posts: 5,425
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Quote:
Originally Posted by cohophysh View Post
I am no mechanic, but what about changing the the cassette in addition to the front chain ring to something similar to a mtb set up but still maintain the roadie components.
The problem is one of compatibility. As mentioned previously, most rear derailleurs designed for road bikes can't handle the large cogs on a MTB cassette. There's a similar problem with front derailleurs. I forget the exact numbers but I think a triple FD for a road bike can only handle a difference of 22 teeth between the small chain ring and the large. For a double FD, I think it's... 16 teeth?
sstorkel is offline   Reply With Quote
Old 07-28-08, 09:29 AM   #14
Iamkar33m
Senior Member
 
Join Date: Jun 2008
Bikes:
Posts: 725
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I have a Specialized Tricross, the Rear Cassette is a Shimano 9spd 11-34t... however it utilizes a MTB Shimano Deore LX Rear Derailleur (Long Cage). The Crank is a triple chainring 50x39x30T set, with a Tiagra Front Derailleur.

The Tricross is a Road bike built for off-road riding (cyclocross), so I have no doubt that you can put mountain gearing on a road bike... you just might have to replace some additional parts to get it to work properly.
Iamkar33m is offline   Reply With Quote
Old 07-28-08, 09:33 AM   #15
ssridinyob
Newbie
 
Join Date: Jun 2008
Location: Northern California
Bikes: A big boingy one, a skinny one, a few gear-challenged ones.
Posts: 2
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Salsa makes a 26T granny chainring that could be of significant help, but you have to shift down to it with a little finesse. If that isn't enough, do the mountain cassette and rear derailleur as well. You may well be able to ride up a vertical wall with that combination.
ssridinyob is offline   Reply With Quote
Old 07-28-08, 09:53 AM   #16
77midget
me ride bike good
 
Join Date: Jun 2008
Location: outside Boston, MA
Bikes: Trek 4300
Posts: 462
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
This is one area where my MTB commuter shines. I hit a bunch of hills, and I never run out of gears-normally stay in 2-3 2-4 for extended climbs, but it is nice to know that the small ring is there if I ever need it.
77midget is offline   Reply With Quote
Old 07-28-08, 01:12 PM   #17
sstorkel
Senior Member
 
Join Date: Apr 2008
Bikes: Cervelo RS, Specialized Stumpjumper FSR Pro, Schwinn Typhoon, Nashbar touring, custom steel MTB
Posts: 5,425
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Quote:
Originally Posted by ssridinyob View Post
Salsa makes a 26T granny chainring that could be of significant help, but you have to shift down to it with a little finesse. If that isn't enough, do the mountain cassette and rear derailleur as well. You may well be able to ride up a vertical wall with that combination.
Remember that the front derailleur places limits on what chain rings you can use. In the case of Shimano, most double chain ring FDs only support a 16-tooth difference between the smallest chain ring and the largest. A triple chain ring FD will support a 22-tooth difference. Which means that if you opt for the 26-tooth chain ring, your max is limited to either 42 or 48 teeth. My guess is that if you need a 26-tooth chain ring to get up a hill, you're going to want a large chain ring with more than 48 teeth on the descent...
sstorkel is offline   Reply With Quote
Old 07-28-08, 04:11 PM   #18
DieselDan
Senior Member
 
DieselDan's Avatar
 
Join Date: Mar 2003
Location: Beaufort, South Carolina, USA and surrounding islands.
Bikes: Cannondale R500, Motobecane Messenger
Posts: 8,521
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Easy done with a Shimano Deore, XT, or XTR rear derailer, as the pull ratio is the same. Couple that with a 28/38/50 crankset and you'll be good to go.

Last edited by DieselDan; 07-29-08 at 08:41 AM.
DieselDan is offline   Reply With Quote
Old 07-28-08, 05:35 PM   #19
Bill Kapaun
Senior Member
 
Bill Kapaun's Avatar
 
Join Date: Feb 2007
Location: Mid Willamette Valley, Orygun
Bikes: 86 RockHopper,2008 Specialized Globe. Both upgraded to 9 speeds.
Posts: 9,198
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 12 Post(s)
Quote:
Originally Posted by ModelT View Post
Experimental results:

I mounted an 8 speed mountain wheel with a 13-32 cassette on the bike to see what would happen.
(No riding here, just slow, no-load spinning to see what the rear derailleur would do)

It did actually shift up to the 32 cog, but made a lot of noise. I might try CliftonGK1's advice and try an 11-32 nine speed and see how much clearance the B screw can provide.

"I know just enough to be dangerous"
Did you lengthen your chain first?
IF the chain was properly sized for a 25T cog, it'll be about 3-4 links too short for a 32T cog.
That can cause damage to the RDER, in addition to "noise", if you try shifting to BIG:BIG.
Noise could be also caused by a slight difference in cassette alignment between different wheel sets, even between 2 different 9 speeds.
Bill Kapaun is offline   Reply With Quote
Old 07-28-08, 06:39 PM   #20
cyccommute 
Mad bike riding scientist
 
cyccommute's Avatar
 
Join Date: Nov 2004
Location: Denver, CO
Bikes: Some silver ones, a black one, a red one, an orange one and a couple of titanium ones
Posts: 17,832
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 82 Post(s)
Quote:
Originally Posted by ssridinyob View Post
Salsa makes a 26T granny chainring that could be of significant help, but you have to shift down to it with a little finesse. If that isn't enough, do the mountain cassette and rear derailleur as well. You may well be able to ride up a vertical wall with that combination.
The bolt ring circle on most road cranks is capable of handling a 24 tooth ring. A cassette change may get you to a 29 or 30 tooth on the cassette without too many problems. Changing to a mountain bike rear derailer isn't hard or expensive. Jenson USA sells a Deore for $20.
__________________
Stuart Black
New! Pokin' around the Poconos A cold ride around Lake Erie
New! Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
Days of Wineless Roads. Bed and Breakfasting along the KATY
Twisting Down the Alley. Misadventures in tornado alley.
An Good Ol' Fashion Appalachian Butt Whoopin'.
cyccommute is offline   Reply With Quote
Old 07-28-08, 06:42 PM   #21
cyccommute 
Mad bike riding scientist
 
cyccommute's Avatar
 
Join Date: Nov 2004
Location: Denver, CO
Bikes: Some silver ones, a black one, a red one, an orange one and a couple of titanium ones
Posts: 17,832
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 82 Post(s)
Quote:
Originally Posted by sstorkel View Post
Remember that the front derailleur places limits on what chain rings you can use. In the case of Shimano, most double chain ring FDs only support a 16-tooth difference between the smallest chain ring and the largest. A triple chain ring FD will support a 22-tooth difference. Which means that if you opt for the 26-tooth chain ring, your max is limited to either 42 or 48 teeth. My guess is that if you need a 26-tooth chain ring to get up a hill, you're going to want a large chain ring with more than 48 teeth on the descent...
I've run 52 outers and 24 tooth inners without problems. The front derailer will handle the difference. Shimano is waaaay conservative on their tooth differences.
__________________
Stuart Black
New! Pokin' around the Poconos A cold ride around Lake Erie
New! Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
Days of Wineless Roads. Bed and Breakfasting along the KATY
Twisting Down the Alley. Misadventures in tornado alley.
An Good Ol' Fashion Appalachian Butt Whoopin'.
cyccommute is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 11:46 PM.